B3600
DTC B3600
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions Diagnostic Procedure Instructions provides an overview of each diagnostic category.
DTC Descriptor
DTC B3600 03
-
Passenger Compartment Dimming Request Signal Circuit Voltage Below Threshold
Diagnostic Fault Information
Circuit/System Description
The instrument panel (I/P) dimmer switch is used to increase and decrease the brightness of the interior backlighting components. The body control module (BCM) supplies a 12-volt reference through the instrument panel (I/P) dimming voltage reference circuit to the interior lamp dimmer switch, which is part of the headlamp switch. When the dimmer switch is placed in a desired brightness position, reference voltage is applied through the dimmer switch rheostat and the I/P lamps dimmer switch signal circuit to the BCM. The BCM interprets this voltage signal, then applies a pulse width modulated (PWM) voltage through the I/P lamps control circuit and the LED dimming control circuit to all related interior lamps, illuminating them to the desired level of brightness.
Conditions for Running the DTC
The ignition is ON.
Conditions for Setting the DTC
* The BCM detects a short to ground or open in the 12-volt reference circuit.
* The BCM detects a short to ground or open in the I/P dimming signal circuit.
Action Taken When the DTC Sets
The I/P lamps are not illuminated.
Conditions for Clearing the DTC
A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred.
Reference Information
Schematic Reference
Interior Lights Dimming Schematics Interior Lights Dimming Schematics
Connector End View Reference
Component Connector End Views A/C Compressor Clutch
Description and Operation
Interior Lighting Systems Description and Operation Interior Lighting Systems
Electrical Information Reference
* Circuit Testing Circuit Testing
* Connector Repairs Connector Repairs
* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs Wiring Repairs
Scan Tool Reference
Control Module References Programming and Relearning for scan tool information
Circuit/System Verification
Ignition ON, cover the ambient light sensor, vary the interior lamp dimming switch from dim to full bright. The I/P lamps should dim and then become full bright.
Circuit/System Testing
1. Ignition OFF, disconnect the harness connector at the headlamp switch.
2. Ignition OFF, verify a test lamp illuminates between B+ and the ground circuit terminal 8
• If less test lamp does not illuminate, test the ground circuit for an open/high resistance.
3. Ignition ON, test for B+ between the B+ circuit terminal 15 and ground.
• If less than the specified range, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
4. Verify the scan tool Dimming Control Signal parameter is less than 0.2 volts.
• If greater than the specified range, test the signal circuit terminal 13 for a short to voltage. If the circuit tests normal, replace the BCM.
5. Install a 3A fused jumper wire between the signal circuit terminal 13 and the B+ circuit terminal 15. Verify the scan tool Dimming Control Signal parameter is greater than 2.5 volts.
• If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
6. If all circuits test normal, test or replace the headlamp switch.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.
* Headlamp Switch Replacement Service and Repair
* Control Module References Programming and Relearning for BCM replacement, setup, and programming